The customer authorization (provided in the link you clicked) is out of date, and does not entitle you to use the Blended Threat service.
https://www.gov.uk/guidance/getting-eu-funding?utm_source=29c07c9d-62d3-4fc4-915f-d8944ea7824d&utm_medium=email&utm_campaign=govuk-notifications&utm_content=immediate